function s1_gernerate_a_series_of_files(){
	for i in $(seq 1 100); do
		echo $i>/tem/new_file$i; done
}
function s2_list_4_files_in_long_about_account_and_group(){
	ls -l /etc/passwd /etc/shadow/ etc/group/ rtc/gshadow | sort -d
}
function s3_find_items_related_to_given_username(){
	grep -h $1 /etc/passwd /etc/shadow | sort -d
}
function s4_find_items_ralated_to_given_group_name(){
	grep -h $1 /etc/group /etc/gshadow | sort -d
}
function s5_create_groups_for_given_group_names(){
	groupadd rnd && groupadd itoperation
}
function s6_create_users_and_set_their_group_as_required(){
	useradd -G rnd adam && useradd -G rnd bob && useradd -G itoperation calvin && useradd -G itoperation david && useradd -G rnd edward
}
function s7_change_users_shell(){
	usermod -s /usr/bin/sh adam
	usermod -s /usr/bin/sh edward
}
function s8_set_password_change_policy(){
	passwd -n 10 -x 60 -w 10 adam
	passwd -n 10 -x 60 -w 10 bob
	passwd -n 10 -x 60 -w 10 calvin
	passwd -n 10 -x 60 -w 10 david
	passwd -n 10 -x 60 -w 10 edward
}
function s9_set_password_for_five_user(){
	usernames=(adam bob calvin david edward)
	for i in $(seq 1 5); do echo ${!i}; echo $(($i-1)); done
	echo "${usernames[0]}:$1" | chpassword
	echo "${usernames[1]}:$2" | chpassword
        echo "${usernames[2]}:$3" | chpassword
        echo "${usernames[3]}:$4" | chpassword
        echo "${usernames[$(($i-1))]}:$5" | chpassword
}
function s10_lock_bobs_password(){
	usermod -L bob
}
function s11_include_adam_into_wheel_group(){
	usermod -a -G wheel adam
}
function s12_change_files_permission(){
	for i in {1..33}; do chmod -R 640 /tmp/new_file$[3*i]; done
}

